Leaching of a silicate and carbonate copper ore with heterotrophic fungi and bacteria, producing organic acids

Abstract

Leaching of metals with carbon-heterotrophic microorganisms and organic acids as active agents has been performed with Timna copper ore containing 1.1% copper as carbonates and silicate and with some other metal oxides. Aspergillus niger surface cultures on a 14% sucrose fermentation medium yeilded 87.3% of total copper from 10% suspension within 2 weeks of leaching. On sulfite liquor as an industrial waste product A. niger solubilized 73.8% Cu within 4 weeks. In percolators with 14% sucrose medium up to 1780 ppm copper were found in solution. In leaching experiments with a sea water medium containing 7% sucrose only 684 ppm Cu were soluble. Leaching with lactobacilli containing whey yielded 83.4% of the total copper in 4 weeks.

Copper and antimony extraction from tetrahedrite‐containing dolomite heterotrophic bacteria

“…Some heterotrophic microorganisms are also characterized by a high metal tolerance. Wenberg et al (1971) and Kiel and Schwartz (1980) reported on copper leaching experiments that were carried out successfully with fungi (yields of 80%). Heterotrophic bacteria were successfully applied in the leaching of manganese and gold (Ehrlich, 1980;Pares, 1968).…”

“…For the reasons mentioned above, the application of heterotrophic microorganisms in leaching silicate/carbonate materials has certain advantages. Weathering experiments have shown that fungi and heterotrophic bacteria grown on silicate and carbonate ores were able to attack and destroy the ores by producing organic acids (Wagner and Schwartz, 1967;Kiel and Schwartz, 1980). Metal leaching in these instances was based on a completely different principle than with T. ferrooxidans.…”

Biocatalytic and chemical leaching of a low-grade nickel laterite ore

“…Biocatalytic activity of A. niger has been reported to be helpful in leaching of metals from ores [40]. Organic acids (oxalic acid, citric acid, gluconic acid, etc.)…”

Dissolution kinetics of nickel laterite ore using different secondary metabolic acids

“…Both autotrophic (Torma and Bosecker, 1982) and heterotrophic (Kiel and Schwartz, 1980;Sukla and Panchanadikar, 1983;Munier-Lamy and Berthelein, 1987) microorganisms possess the potential to remove nickel from its ores.…”